/ Dictionary / Index J jejunum: Meaning and Definition of Find definitions for: je•ju•num Pronunciation: ( ji-j'num), [key] — n. Anat. the middle portion of the small intestine, between the duodenum and the ileum. See diag. under Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: jejunum (Thesaurus) jejunostomy Jekyll and Hyde Related Content Daily Word Quiz: inutiae Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language